This invention relates to methods and apparatus for processing stators for electric motors and similar machines such as generators. Although the invention is described herein in the context of its application to electric motor stators, it will be understood that it is equally applicable to other types of stators such as have been mentioned.
In a typical stator manufacturing process, wire is wound into coils around the poles of the stator body and the ends of the coil wires are subsequently anchored to the terminal receptacles of the stator. While the stator is in the winding station, the ends of the coil wires must temporarily be gripped to avoid loosening of the coils. The actual anchoring of the leads to the terminals is carried out by a separate machine which performs the termination cycle by removing the leads from the grippers and relocating them to the terminals.
It follows that the stator must be transported between the winding machine and the anchoring machine on some sort of transport device with the leads temporarily anchored to grippers which must be maintained in a fixed position in relation to the stator in order to avoid loosening of the coils.
In the past, the elements for temporarily gripping the ends of the coil wires have been provided on the pallets or other structures which support and/or convey the stators. Providing elements for temporarily holding the ends of the wire coils on the pallet or other coil supporting structure has a number of disadvantages. For one thing, these wire holding elements complicate the pallet, thereby increasing its cost. The presence of these wire gripping elements around the stator also makes it more difficult to place the stator on or remove the stator from the pallet. The stator handling elements which perform these tasks must be designed so that they do not interfere with the wire gripping elements. The need for wire gripping elements on the pallet may make it difficult or impossible to use the same pallet for stators of different size (e.g., different stack height). A substantial amount of wire may be needed to temporarily reach wire gripping elements on the pallet. This wire may have to be cut off and discarded when the wire is finally permanently terminated on the terminal board. The fact that the coil ends are temporarily attached to the pallet may make it more difficult or impossible to use certain permanent termination techniques which would otherwise be advantageous. For example, it may be difficult or impossible to employ permanent termination apparatus which requires removal of the stator from the pallet.
These problems were presented and discussed in Santandrea et al. U.S. Pat. No. 4,994,697, and Ser. No. 07/385,570, filed Jul. 26, 1989. Application U.S. Pat. No. 4,994,697 discloses terminal boards, which are insulating members typically placed on both axial ends of the main stator body, for temporarily holding the ends of the coil wires during and after winding the coils on the poles of a stator.
Using terminal boards having anchoring grippers to temporarily hold the ends of the coil wires in place is viable, but in some cases that method may have certain limitations. Because stators in use today often require that a greater number of coils be wound around the stator poles than in the past, the terminal boards do not always provide sufficient space to receive the grippers. For the same reason, the gripper position often cannot be chosen to suit an ideal wire manipulation.
In view of considerations such as the foregoing, it is an object of this invention to provide improved methods and apparatus for temporarily holding the ends of coil wires during and after winding the coils on the poles of a stator.
Another method of temporarily gripping the ends of coil wires during processing involves locating the grippers on the stator transport pallet. However, this requires precise positioning of the pallet at both the winding and the termination stations in order to process the stator without removing it from the pallet. Thus, it is another object of this invention to provide an alternative to locating the temporary grippers on the stator transport pallet.